Tape head read/write module

ABSTRACT

A tape head read/write module that has a composite air bearing surface, and a method and apparatus for embedding a chip in a substrate to form a composite air bearing surface. An example of the module includes a substrate that has an air bearing surface, a front, a back, and a chip receiving slot. The air bearing surface of the substrate has a first portion adjoining a first side of the chip receiving slot, and a second portion adjoining a second side of the chip receiving slot. The module also includes a chip that has an air bearing surface, a bottom surface, a front, a back, and active elements. The active elements are located proximate the front of the chip. The chip is positioned in the chip receiving slot in the substrate, with the air bearing surface of the chip substantially aligned with the air bearing surface of the substrate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/449,443 filed Jun. 7, 2006 , now U.S. Pat. No. 7,274,536 titled “Tapehead read/write module”, which is hereby incorporated herein by thisreference, which is a divisional of U.S. patent application Ser. No.10/431,247 filed May 6, 2003, now U.S. Pat. No. 7,082,013 titled “Methodand apparatus for embedding a chip in a substrate to form a compositeair bearing surface”, which is hereby incorporated herein by thisreference.

BACKGROUND

1. Technical Field

The present invention relates to heads used to write and retrieveinformation on magnetic storage tape media. More particularly, theinvention concerns a method for embedding a chip that has activeelements, in a substrate, to form a composite air bearing surface thatmay be used, for example, in a tape head.

2. Description of Related Art

Magnetic tape is widely used for storing data in computing systems. Tapeheads are used for writing information to the tape and readinginformation from the tape. A tape head typically includes two modulesthat each have a plurality of reading and writing elements, that may becalled active elements. In each module, the reading and writing elementsare formed in a substrate that has a smooth air bearing surface (ABS)which makes contact with and supports the flexible tape as it travels.This type of tape head may be called a contact recording tape head. Tominimize the occurrence of decreased signals from spacing losses, damageto the tape, and other problems, the air bearing surface of each modulemust be very smooth, so that the tape can pass over each module in closeproximity to the reading and writing elements. Because of its degree ofsmoothness, an air bearing surface may be referred to as being opticallypolished.

Because the reading and writing elements in each module span only asmall portion of the tape width, during operation the tape head is movedlaterally so that the substrate in each module moves laterally acrossthe tape to line up the reading and writing elements with the tracks onthe tape that are being read from or written to. Consequently, thesubstrates are wider than the width of the tape, and are considerablywider than the portion of the tape spanned by the reading and writingelements, to maintain support of the tape surface and to avoidpotentially tearing the tape with sharp edges while lining up thereading and writing elements with tracks that are not in the center ofthe tape.

Traditionally, the reading and writing elements and the substrate of amodule are formed in a semiconductor wafer. Forming the substrate in thewafer requires a much larger area of the wafer than is required for thereading and writing elements. Due to the high cost of wafer space,forming the substrate in the wafer substantially increases the cost ofmaking a module. Consequently, existing methods for making tape headsare not completely cost effective.

SUMMARY

One aspect of the invention is a method for embedding a chip in asubstrate, to form a composite air bearing surface. An example of themethod includes securing the substrate in a fixed position, and aligningthe chip in a first direction with a chip receiving slot in thesubstrate. The method also includes depositing adhesive in the chipreceiving slot in the substrate, and aligning the chip in a seconddirection with the chip receiving slot in the substrate. The chip isthen pushed into the adhesive in the chip receiving slot. The methodfurther includes detecting when an air bearing surface of the chip issubstantially at a desired protrusion in a third direction in relationto an air bearing surface of the substrate. Responsive to detecting thatthe air bearing surface of the chip is substantially at the desiredprotrusion in the third direction in relation to the air bearing surfaceof the substrate, the operation of pushing the chip into the adhesive isceased. The adhesive is at least partially cured to bond the chip to thesubstrate with the air bearing surface of the chip substantially at thedesired protrusion in the third direction, and with the chipsubstantially aligned in the first and second directions with chipreceiving slot in the substrate.

Another aspect of the invention is a tape head read/write module thathas a composite air bearing surface. The module includes a substratethat has an air bearing surface, a front, a back, and a chip receivingslot. The chip receiving slot has a front at the front of the substrate,a back at the back of the substrate, a first side, a second side, and abonding surface. The air bearing surface of the substrate has a firstportion adjoining the first side of the chip receiving slot, and asecond portion adjoining the second side of the chip receiving slot. Themodule also includes a chip that has an air bearing surface, a bottomsurface, a front, a back, and active elements. The active elements arelocated proximate to the front of the chip. The chip is inserted in thechip receiving slot in the substrate, with the air bearing surface ofthe chip substantially aligned with the air bearing surface of thesubstrate, and with the back of the chip substantially aligned with theback of the substrate.

Other aspects of the invention are described in the sections below, andinclude, for example, an apparatus for aligning and bonding a chip witha substrate to form a composite air bearing surface.

The invention provides a number of advantages. The invention permitsmaking a composite air bearing surface by embedding a chip that hasreading and writing elements, in a substrate, which makes it unnecessaryto form the substrate in the expensive semiconductor wafer with thechip. Because the substrate is much larger than the chip and is not madein the wafer, a larger number of chips can be made in the wafer, whichadvantageously reduces the cost of each chip. Additionally, a largernumber of chips can be produced in each row on the wafer, andconsequently, the lapping cost per chip is lowered because a largernumber of chips can be simultaneously lapped. Further, the composite airbearing surface does not require lapping after the chip is embedded inthe substrate, which can be an expensive operation. The invention alsoprovides a number of other advantages and benefits, which should beapparent from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a chip embedded in a substrate to form acomposite air bearing surface in accordance with an example of theinvention.

FIG. 2 is a top view of a chip embedded in a substrate to form acomposite air bearing surface in accordance with an example of theinvention.

FIG. 3 is a front view of a chip embedded in a substrate to form acomposite air bearing surface in accordance with an example of theinvention.

FIG. 4 is a sectional view taken along the line 4-4 in FIG. 3, of a chipembedded in a substrate to form a composite air bearing surface inaccordance with an example of the invention.

FIG. 5 is a perspective view of an apparatus for aligning and bonding achip with a substrate in accordance with an example of the invention.

FIG. 6 is a cutaway perspective view of a portion of an apparatus foraligning and bonding a chip with a substrate in accordance with anexample of the invention.

FIG. 6A is another cutaway perspective view of a portion of an apparatusfor aligning and bonding a chip with a substrate in accordance with anexample of the invention.

FIG. 7 is a bottom perspective view of a pick-up chuck of an apparatusfor aligning and bonding a chip with a substrate, in accordance with anexample of the invention.

FIG. 8 is a side view of an adhesive dispenser attached to a base inaccordance with an example of the invention.

FIGS. 9A and 9B are a flowchart of an operational sequence for embeddinga chip in a substrate to form a composite air bearing surface inaccordance with an example of the invention.

DETAILED DESCRIPTION

The nature, objectives, and advantages of the invention will become moreapparent to those skilled in the art after considering the followingdetailed description in connection with the accompanying drawings.

I. HARDWARE COMPONENTS AND INTERCONNECTIONS A. Tape Head Module

One aspect of the invention concerns a read/write module that has acomposite air bearing surface that may be used, for example, in a tapehead. As an example, the read/write module may be embodied by the module100 shown in FIGS. 1-4. FIG. 1 is a perspective view of the module 100,FIG. 2 is a top view of the module 100, FIG. 3 is a front view of themodule 100, and FIG. 4 is a sectional view of the module 100 taken alongthe line 4-4 in FIG. 3. The module 100 includes a composite air bearingsurface 102, a substrate 104, a chip 106, and a closure 108. As anexample, the substrate 104 and chip 106 may both be made of N58 AlTiC.The substrate 104 has a substrate air bearing surface 110 that has afirst portion 112 and a second portion 114. The substrate 104 also has abottom 116, a front 118, a back 120, a first side 122, a second side124, and a chip receiving slot 126. The chip 106 has a chip air bearingsurface 128, a bottom surface 130 (shown most clearly in FIGS. 3 and 4),a front 132 of the chip 106, a front 133 of the chip air bearing surface128, a back 134, a first side 136, and a second side 138. The substrateair bearing surface 110 and the chip air bearing surface 128 togetherform the composite air bearing surface 102. The chip 106 also has afirst front corner 139 a (shown most clearly in FIG. 2), a second frontcorner 139 b, a first back corner 139 c, and a second back corner 139 d.The chip 106 also has active elements 140 (shown most clearly in FIGS. 2and 4) that are located proximate to the front 132 of the chip 106.Accordingly, the chip 106 may be referred to as an active element chip.The active elements 140 in the chip 106 may include, for example, eightreaders, eight writers, and two servos. However, the active elements 140could include larger or smaller numbers of readers, writers, and/orservos. The readers may be, for example, magneto resistive (MR)elements. The readers may also be called sensors. The closure 108 has aclosure air bearing surface 141, a front 142, and a back 144, and theback 144 of the closure 108 is attached to the front 132 of the chip106. Electrical leads (not shown) for the active elements 140 may becoupled to pads 145 on the front 132 of the chip 106 beneath the closure108. In order to provide connections to the active elements 140, thenumber of pads 145 provided on the chip 106 may be greater than thenumber of pads 145 shown in FIG. 3.

The length of the substrate 104 from the first side 122 of the substrate104 to the second side 124 of the substrate 104 may be, for example,about 22.5 mm. The height of the substrate from the bottom 116 of thesubstrate 104 to the air bearing surface 110 of the substrate 104 maybe, for example, about 2.5 mm. The distance from the front 118 to theback 120 of the substrate 104 (the width of the substrate 104) may be,for example, about 2.0 mm. The substrate 104 may also include a firstfront protrusion 146 that has a face 148, and a second front protrusion150 that has a face 152. The distance from the face 148 of the firstfront protrusion 146 and the face 152 of the second front protrusion 150to the back 120 of the substrate 104 may be, for example, about 2.75 mm.The air bearing surface 110 of the substrate 104 has a back edge 154.The distance from the front 118 of the substrate 104 to the back edge154 of the air bearing surface 110 on the substrate 104 may be, forexample, about 0.63 mm, and in another example could be, for exampleabout 0.80 mm. However, other distances could be utilized.

The tape used with the module 100 may, as an example, be about 1.27 cm(0.5 inch) wide. However, different tape widths could be used, and, ifnecessary, the width of the substrate 104 could be adjusted toaccommodate different tape widths.

The length of the chip 106 from the first side 136 of the chip 106 tothe second side 138 of the chip 106 may be, for example, about 6.8 mm.The thickness of the chip 106 from the bottom surface 130 of the chip106 to the air bearing surface 128 of the chip 106 may be, for example,about 550±15 μm. The distance from the front 132 to the back 134 of thechip 106 (the width of the chip 106) may be, for example, about 2.0 mm.Thus, the bonding area on the bottom surface 130 of the chip 106 may beabout 6.8 mm by about 2.0 mm. The air bearing surface 128 of the chip106 has a back edge 156. The distance from the front 132 of the chip 106to the back edge 156 of the air bearing surface 128 on the chip 106 maybe, for example, about 0.63 mm, and in another example could be, forexample 0.80 mm. However, other distances could be utilized. Thedistance from the front 142 to the back 144 of the closure 108 may be,for example, about 0.225 mm.

In the module 100 shown in the illustrated example, the chip 106 has atail surface 157 that may be substantially parallel to the air bearingsurface 128 of the chip 106 and the air bearing surface 110 of thesubstrate 104. Similarly, the substrate 104 has a tail surface 158 thathas a first portion 159 adjoining a rear portion of the first side 166of the chip receiving slot 126, and a second portion 160 adjoining arear portion of the second side 168 of the chip receiving slot 126. Thetail surface 158 of the substrate 104 is substantially coplanar with thetail surface 157 of the chip 106. The tail surfaces 157, 158 do not haveto be parallel to the air bearing surfaces 128, 110. The tail surface157 of the chip 106 is located between the air bearing surface 128 ofthe chip 106 and the back 134 of the chip 106, and is located in a planepositioned between the air bearing surface 128 of the chip 106 and thebottom surface 130 of the chip 106. Similarly, the tail surface 158 ofthe substrate is located between the air bearing surface 110 of thesubstrate 104 and the back 120 of the substrate 104. The tail surface157 of the chip 106 and tail surface 158 of the substrate 104 may beformed by a taperless grind operation, discussed below, in which asubstantially rectangular rear portion of the composite air bearingsurface 102 is removed. The chip tail surface 157 and the substrate tailsurface 158 may be, for example, about 0.18 mm from the plane defined bythe air bearing surface 128 of the chip 106. The distance from the back134 of the chip 106 to a front edge 161 of the tail surface 157 of thechip 106, and from the back 120 of the substrate 104 to a front edge 162of the tail surface 158 of the substrate 104, may be, for example, about1.75 mm.

As shown most clearly in FIGS. 3-4, the chip receiving slot 126 in thesubstrate 104 has a front 163 at the front 118 of the substrate 104, aback 164 at the back 120 of the substrate 104, a first side 166, asecond side 168, and a bonding surface 170. The chip receiving slot 126also has a first side trough 172 proximate to the first side 166 of thechip receiving slot 126, and a second side trough 174 proximate to thesecond side 168 of the chip receiving slot 126. The first side trough172 has a bottom 176, and the second side trough 174 has a bottom 178.The depth of the chip receiving slot 126 is chosen so that the airbearing surface 128 of the chip 106 will be substantially aligned withthe air bearing surface 110 of the substrate 104 over the temperatureand humidity ranges to which the module 100 is likely to be exposed,despite expansion or contraction of the adhesive and tolerancevariations in the thickness of the chip 106. In the illustrated example,when the chip 106 is placed in the chip receiving slot 126, the back 134of the chip 106 is aligned with the back 164 of the chip receiving slot126. However, the chip 106 does not have to extend to the back 164 ofthe chip receiving slot 126. The length of the chip receiving slot 126from the first side 166 of the chip receiving slot to the second side168 of the chip receiving slot 126 may be, for example about 7.0 mm,and, for example, is centered along the 22.5 mm length of the substrate104. The width of the chip receiving slot 126 from the front 163 of thechip receiving slot 126 to the back 164 of the chip receiving slot 126may be, for example, about 2.0 mm. The distance from the air bearingsurface 110 of the substrate 104 to the bonding surface 170 of the chipreceiving slot 126 may be, for example, about 580±15 μm. The distancefrom the air bearing surface 110 of the substrate 104 to the bottom 176of the first side trough 172 and to the bottom 178 of the second sidetrough 174 may be, for example about 0.65 mm.

The first portion 112 of the substrate 104 air bearing surface 110adjoins the first side 166 of the chip receiving slot 126, and thesecond portion 114 of the substrate 104 air bearing surface 110 adjoinsthe second side 168 of the chip receiving slot 126. The chip 106 isinserted in the chip receiving slot 126 in the substrate 104 with theair bearing surface 128 of the chip 106 substantially aligned with theair bearing surface 110 of the substrate 104, and with the back 134 ofthe chip 106 substantially aligned with the back 120 of the substrate104.

An adhesive layer 180 (shown most clearly in FIGS. 3 and 4) is attachedto the bonding surface 170 of the chip receiving slot 126 and to thebottom surface 130 of the chip 106. As an example, the adhesive layer180 may be U.V. cured. Additionally, the adhesive layer 180 fills atleast a portion of the first side trough 172 and/or the second sidetrough 174.

B. Apparatus for Aligning and Bonding a Chip with a Substrate

Another aspect of the invention concerns an apparatus for aligning andbonding a chip 106 with a substrate 104 to form a composite air bearingsurface 102. The apparatus may be called a bonding apparatus, a bondingmachine, or a fixture. As an example, the apparatus may be embodied bythe apparatus 500 shown in FIG. 5. FIG. 5 is a perspective view of theapparatus 500, FIGS. 6 and 6A are cutaway perspective views of portionsof the apparatus 500, and FIG. 7 is a bottom perspective view of apick-up chuck 502 of the apparatus 500. The apparatus 500 includes ahousing 504 that has a substrate seat 506 (shown most clearly in FIG.6A). In FIG. 6 the substrate 104 is shown in the substrate seat 506, andin FIG. 6A the substrate seat 506 is shown without the substrate 104.The substrate seat 506 has back surfaces 508 a, 508 b, 508 c, 508 d(which can be called datums or stops), a bottom 510, a front edge 511,and a side 512 (all shown most clearly in FIG. 6A). In alternativeembodiments, the substrate seat 506 could have one, two, three, or fiveor more back surfaces. The apparatus 500 may also include a substratefront clamp 514 (shown most clearly in FIG. 6) slidably mounted on thehousing 504 for selectively holding the substrate 104 in the substrateseat 506, and a substrate side clamp 516 (shown most clearly in FIGS. 6and 6A) slidably mounted on the housing for selectively holding thesubstrate 104 in the substrate seat 506. The apparatus 500 also includesan alignment arm 518 (shown in FIGS. 5 and 6) slidably attached to thehousing 504. The pick-up chuck 502 (shown most clearly in FIGS. 5 and 7)is slidably attached to the alignment arm 518. The pick-up chuck 502 hasbottom surface 520 (shown in FIG. 7). A first alignment foot 522, and asecond alignment foot 524 (shown in FIG. 7), are attached to the pick-upchuck 502, and protrude from the bottom surface 520 of the pick-up chuck502. The first alignment foot 522 has a bottom surface 526, and thesecond alignment foot 524 has a bottom surface 528. In alternativeembodiments, more than two alignment feet could be used. For example,four alignment feet could be used.

A first fiber optic U.V. light guide 530 (shown most clearly in FIG. 5)is attached to the housing 504. A first end 532 of the first fiber opticU.V. light guide 530 is located proximate to the front edge 511 of thesubstrate seat 506 about 2 mm above the bottom 510 of the substrate seat506. A second end 534 of the first fiber optic U.V. light guide 530 isconfigured for coupling to a U.V. light source (not shown). Similarly, asecond fiber optic U.V. light guide 536 may also be attached to thehousing 504. A first end 538 of the second fiber optic U.V. light guide536 is located proximate to the front edge 511 of the substrate seat 506about 2 mm above the bottom 510 of the substrate seat 506, and a secondend 540 of the second fiber optic U.V. light guide 536 is configured forcoupling to the U.V. light source. A third fiber optic U.V. light guide542 may also be attached to the housing 504. A first end 544 of thethird fiber optic U.V. light guide 542 is located proximate to the backsurfaces 508 b, 508 c of the substrate seat 506, and a second end 546 ofthe third fiber optic U.V. light guide 542 is configured for coupling tothe U.V. light source. The U.V. light guides may also be called wands.

The bottom surface 520 (shown in FIG. 7) of the pick-up chuck 502 mayhave a hole 548 for coupling to a vacuum source (not shown) for holdingthe air bearing surface 128 of the chip 106 against the bottom surface520 of the pick-up chuck 502. Additionally, a chip seat 550 (shown mostclearly in FIG. 6) that has a slot 552 for receiving the chip 106, maybe formed in the housing 504, for aligning the chip 106 in a y direction(which may also be referred to as a first direction) and for holding thechip 106 before it is picked up by the pick-up chuck 502. The chip seat550 may have a hole 554 for coupling to the vacuum source, for holdingthe chip 106 on the chip seat 550.

The apparatus 500 may also include an adhesive dispenser 556 and a base557, which are shown in FIG. 8. The base 557 may be attached to thehousing 504. The adhesive dispenser 556 has a hole 558 (which may alsobe called an opening), for dispensing adhesive. The adhesive dispenser556 is attached to a first dispenser holder arm 559, and a seconddispenser holder arm 560, which are attached to a dispenser stand 561.The adhesive dispenser 556 may be selectively coupled to an air pressuresource (not shown) for pushing the adhesive out of the hole 558 of theadhesive dispenser 556. As an example, an air tube (not shown) may becoupled to the adhesive dispenser for supplying air pressure from an airpressure source for pushing the adhesive out of the hole 558. Theadhesive dispenser may 556 be attached to actuators (not shown) formoving the hole 558 in the adhesive dispenser 556 over the chipreceiving slot 126 in the substrate 104 to deposit adhesive in the chipreceiving slot 126. As an example, three electrical actuators may beattached to the dispenser stand 561 for moving the adhesive dispenser556 in x, y, and z directions. The x direction may be referred to as asecond direction, the y direction may be referred to as a firstdirection, and the z direction may be referred to as a third direction.

Movement of the alignment arm 518 may be accomplished, for example, bycoupling an air pressure source to a cylinder (not shown) attached to,or formed in, the alignment arm 518. As an example, a tube may be usedto couple air from an air compressor to the cylinder. Air pressure maybe applied to one side of the cylinder to move the cylinder and thealignment arm 518 in a first direction, and may be applied to anopposite side of the cylinder to move the cylinder and the alignment arm518 in an opposite direction. The substrate front clamp 514 and thesubstrate side clamp 516 may, for example, be moved in a similar fashionwith air pressure. Bearings (not shown) may be utilized to facilitatesmooth movement of the alignment arm 518. Vertical movement of thepick-up chuck 502 may be accomplished, for example, with an air bladder562 coupled to the pick-up chuck 502 with a pivot arm 564. The airbladder 562 may be coupled to an air pressure source (not shown) forinflating and deflating the air bladder 562. For example, the pick-upchuck 502 may be moved downward by putting air into the air bladder 562,and may be moved upward by removing air from the air bladder 562. Airlines, valves, switches, manifolds, and pressure regulators (not shown),may be utilized to couple the air pressure source (or air pressuresources) to the alignment arm 518, the bladder 562, the substrate frontclamp 514, the substrate side clamp 517, the hole 548 in the bottomsurface 520 of the pick-up chuck 502, the hole 554 in the chip seat 550,and to the adhesive dispenser 556. The air pressure source may, forexample, provide positive air pressure and/or negative air pressure (tocreate a vacuum source). A processor, for example a portable computer,may be coupled to the air pressure source, valves, and actuators forcontrolling operation of the apparatus 500. Alternatively, electricactuators could be used to move the alignment arm 518, the pick-up chuck502, the substrate front clamp 514, and the substrate side clamp 516.

Alignment of the plane of the air bearing surface 128 of the chip 106with the plane of the air bearing surface 110 of the substrate 104 isaccomplished mechanically with the apparatus 500, by having a portion ofthe apparatus 500 touch the air bearing surface 110 of the substrate 104at specified locations to stop vertical motion of the chip 106, as isdiscussed below. To maintain optimal performance, the fixture 500 couldbe periodically realigned, and a mechanized (or manual) fixture cleaningprocess could be used to clean the fixture 500 between uses.

II. OPERATION

In addition to the various hardware embodiments described above, anotheraspect of the invention concerns a method for embedding a chip in asubstrate, to form a composite air bearing surface, which may be used ina tape head. Embedding the chip in the substrate may also be referred toas merging the chip with the substrate.

Overall Sequence of Operation

For ease of explanation, but without any intended limitation, the methodaspect of the invention is described with reference to the read/writemodule 100 and the apparatus 500 described above. An example of themethod aspect of the present invention is illustrated in FIGS. 9A and9B, which show a sequence 900 for a method for embedding a chip 106 in asubstrate 104 to form a composite air bearing surface 102.

The sequence 900, may begin with the operation 902 of attaching aclosure 108 to the chip 106, adjacent the active elements 140 in thechip 106. The closure 108 is attached to the front 132 of the chip.However, the closure 108, which is included for example to reduce tapewear on the active elements 140, is not required. The sequence 900 mayalso include the operation 904 of lapping the chip 106 to form the airbearing surface 128 on the chip 106, prior to performing the aligningoperation 914 discussed below. The sequence 900 may further includelapping the bottom surface 130 of the chip 106, in operation 906, toproduce sufficient surface roughness on the bottom surface 130 toincrease adhesive reliability and bond strength (discussed below).Operation 908 may also be performed, which comprises grinding the chipreceiving slot 126 in the substrate 104, prior to the operation 916 ofdepositing adhesive in the chip receiving slot 126, which is discussedbelow. The sequence 900 may also include the operation 910 of lappingthe substrate 104 to form the air bearing surface 110 on the substrate104, also prior to the operation 916 of depositing adhesive in the chipreceiving slot 126, discussed below. As an example, the air bearingsurface 110 of the substrate 104 may be lapped after the chip receivingslot 126 is ground in the substrate 104, to avoid distortion of the airbearing surface 110 that could result if the chip receiving slot 126 isground in the substrate 104 after the air bearing surface 110 of thesubstrate 104 is lapped. In one example the air bearing surface 110 ofthe substrate 104 is polished to the same Ra as the air bearing surface128 of the chip 106, which may be, for example about 50 Å Ra.

In operation 912, the substrate 104 is secured in a fixed position. Asan example, the substrate 104 may be secured in the substrate seat 506by pressing the substrate front clamp 514 and/or the substrate sideclamp 516 against the substrate, thereby causing the substrate 104 to bepushed against the back surfaces 508 a, 508 b, 508 c, 508 d and the side512 of the substrate seat 506. In some embodiments there may be a hole(not shown) in the bottom 510 of the substrate seat 506, and air may beevacuated from the hole to hold the bottom 116 of the substrate 104against the bottom 510 of the substrate seat 506. A vacuum source couldbe coupled to the hole to evacuate air from the hole.

The sequence 900 also includes operation 914, which comprises aligningthe chip 106 in a y direction (also called the first direction) with thechip receiving slot 126 in the substrate 104. The operation 914 ofaligning the chip 106 in the y direction may be performed before orafter the operation 916 of depositing adhesive (discussed below). Thechip 106 is aligned in the y direction with the chip receiving slot 126when the distance from the first side 136 of the chip 106 to the firstside 166 of the chip receiving slot 126, and the distance from thesecond side 138 of the chip 106 to the second side 168 of the chipreceiving slot, are about the same. Because the distance from the firstside 136 to the second side 138 of the chip 106 is slightly less thanthe distance from the first side 166 to the second side 168 of the chipreceiving slot 126, the chip 106 will fit into the chip receiving slot126 when the chip 106 is later pushed into adhesive in the chipreceiving slot 126 (in operation 922 discussed below). As an example,the chip 106 may be aligned in the y direction by placing the chip 106in the slot 552 in the chip seat 550. The slot 552 is sized andpositioned so that when the chip 106 is placed in the slot 552, thefirst side 136 of the chip 106 is about 0.1 mm towards the center of thechip receiving slot 126 in the y direction from the first side 166 ofthe chip receiving slot 126, and the second side 138 of the chip 106 isabout 0.1 mm towards the center of the chip receiving slot 126 in the ydirection from the second side 168 of the chip receiving slot 126. Thechip 106 may be held in position in the slot 552 by coupling the hole554 in the chip seat 550 to a vacuum source to evacuate air from thehole 554 in the chip seat 550.

In operation 916, adhesive is deposited in the chip receiving slot 126in the substrate 104. Operation 916 may be accomplished by applyingpressure to adhesive in the adhesive dispenser 556 to cause adhesive toflow from the hole 558 in the adhesive dispenser 556, and by moving thehole 558 in the adhesive dispenser 556 over the chip receiving slot 126while adhesive flows from the hole 556. In one example the adhesive isdeposited at least 5 microns thick on the bonding surface 170 of thechip receiving slot 126. However, smaller or larger adhesive thicknessescould be used. In some embodiments the adhesive may be a U.V. curablecyanoacrylate. However, the adhesive does not have to be U.V. curable.Also, the adhesive does not have to be a cyanoacrylate. In one examplethe adhesive may be part number 4303 manufactured by LoctiteCorporation. Loctite 4303 does not require pressing together the partsthat are to be bonded. Other adhesives available from LoctiteCorporation, for example model numbers 4302 or 4205, or adhesivesavailable from other sources, could also possibly be used. In analternative embodiment, a U.V. curable adhesive could be placed onlynear the four corners of the bonding surface 170 of the chip receivingslot 126 to hold the chip 106 in place, and then later a strongeradhesive could be added between the bottom surface 130 of the chip 106and the bonding surface 170 of the chip receiving slot 126 to increasethe bond strength and reliability.

The humidity characteristics of the adhesive affect the functionalityand reliability of the module 100. Adhesives generally shrink whencured, and swell when subjected to humidity. The amount of adhesiveexpansion due to humidity is greater if there is more adhesivethickness. The adsorption of moisture with exposure to elevatedtemperatures and humidities is low for Loctite 4303, and is between0.25% and 0.78% by weight. Loctite 4303 was measured to exhibit lowhumidity expansion of 0.035 mm/mm at 35° C., 95% R.H. (relativehumidity). The adsorbed water causes expansion of the adhesive, whichincreases the protrusion of the air bearing surface 128 of the chip 106,by 3.5±0.4% of the adhesive thickness. For a 60 μm thick adhesive, theexpansion would be 2.1±0.2 μm. Adhesive expansion can also degrade thecohesive strength of the adhesive. Additionally, moisture may diffusealong the interface between the adhesive and the substrate 104 and/orthe chip 106, potentially degrading the adhesive bond strength. Thehumidity properties of the adhesive are of interest because the module100 is subjected to water if the taperless grind operation 936,discussed below, is performed. Furthermore, tape heads used in the datastorage industry are also exposed to variations in ambient environmentalconditions, which include humidity and temperature variations.

The strength of the bond between the substrate 104 and the chip 106 isanother important characteristic that affects the functionality andreliability of the module 100. The break force of the bond between thesubstrate 104 and the chip 106 ideally should be sufficiently large toprevent (or minimize) movement or degradation of the bond duringprocessing of the module 100 and when the module 100 is exposed toenvironmental conditions over the life of the module 100, for examplehumidity and temperature variations. It is desirable to have a tightdistribution of the break force for modules 100 produced in accordancewith the invention. The break force may be measured, for example, byholding the substrate 104 fixed while applying a pseudo-shear force tothe chip 106 until the bond breaks.

The bottom surface 130 of the chip 106 and the bonding surface 170 ofthe chip insertion slot 126 may be made sufficiently rough to improvethe bond strength and humidity properties of the bond. Generally, thebottom surface 130 of the chip 106 is lapped to make as rough of asurface as can be produced without causing excessive wear on the chip106 or excessive bowing of the chip air bearing surface 128. The bondstrength may be improved by lapping the bottom surface 130 of the chip106, for example, with a 6 μm diamond paste to produce a surfaceroughness between about 70 Å Ra and about 205 Å Ra, with an average ofabout 130 Å Ra. As another example, the bond strength may also beimproved by lapping the bonding surface 170 of the chip insertion slot126 to yield a surface roughness of N5-N6, which is 0.8 μm Ra to 1.6 μmRa.

The sequence 900 may also include the operation 918 of evacuating airfrom the hole 548 in the bottom surface 520 of the pick-up chuck 502, topick up the chip 106 and hold the air bearing surface 128 of the chip106 against the bottom surface 520 of the pick-up chuck 502. The chip106 may be picked up by the pick-up chuck 502 to facilitate moving thechip 106 by moving the alignment arm 518. The alignment arm 518 may bemoved in an x direction (also called the second direction) to align thechip 106 in the x direction with the chip receiving slot 126 in thesubstrate 104, in operation 920 (discussed below). The chip 106 may beheld against the pick-up chuck until the U.V. curing (discussed below)is completed. To evacuate air from the hole 548, a vacuum source (notshown) may be coupled to the hole 548 with a tube (not shown). Thevacuum source may be the same vacuum source, or a different vacuumsource than the vacuum source used for evacuating air from the hole 554in the chip seat 550. To facilitate picking up the chip 106 with thepick-up chuck 502, the vacuum source may be decoupled from the hole 554in the chip seat 550 prior to when the chip 106 is picked up by thepick-up chuck 502. The chip 106 remains aligned in the y direction whenit is picked up by the pick-up chuck 502 on the alignment arm 518.

In operation 920 the chip 106 is aligned in the x direction with thechip receiving slot 126 in the substrate 104. The chip 106 may bealigned in the x direction with the chip receiving slot 126 in thesubstrate 104 by substantially aligning the back 134 of chip 106 withthe back 120 of the substrate 104, or, by substantially aligning thefront 133 of the air bearing surface 128 of the chip 106 with the front163 of the chip receiving slot 126. For example, the chip 106 may bealigned with the substrate 104 in the x direction by picking up the chip106 with the pick-up chuck 502, and then moving the pick-up chuck 502and the chip 106 over the substrate 104 until the back 134 of the chip106 touches the back surfaces 508 b, 508 c of the substrate seat 506.Because the substrate 104 has been secured to the substrate seat 506 inoperation 912, the back 120 of the substrate 104 also is touching theback surfaces 508 b, 508 c (and back surfaces 508 a, 508 d) of thesubstrate seat 506.

The sequence 900 also includes the operation 922 of pushing the chip 106into the adhesive in the chip receiving slot 126 of the substrate 104.The pushing operation 922 may be accomplished by lowering the pick-upchuck 502, while holding the chip 106 on the bottom surface 520 of thepick-up chuck 502, with the air bearing surface 128 of the chip 106substantially parallel with the air bearing surface 110 of the substrate104. As an example, in the pushing operation 922 the chip 106 is pushedinto the adhesive only in the negative z direction. The pushingoperation 922 may also include pushing a portion of the adhesive into aplurality of troughs 172, 174 in the chip receiving slot 126 in thesubstrate 104. The adhesive may be pushed into the plurality of troughs172, 174 by the bottom surface 130 of the chip 106 as the chip 106 ispushed into the adhesive. The plurality of troughs 172, 174 are providedso that excessive adhesive will flow into the troughs 172, 174 ratherthan on to the composite air bearing surface 102.

The sequence 900 further includes the operation 924 of detecting whenthe air bearing surface 128 of the chip 106 is substantially at adesired protrusion in the z direction in relation to the air bearingsurface 110 of the substrate 104. The z direction may also be referredto as the third direction. The z direction is perpendicular to the airbearing surface 110 of the substrate 104, and the desired protrusion ofthe air bearing surface 128 of the chip 106 can be a negative, positive,or zero value with reference to the air bearing surface 110 of thesubstrate 104. The detecting operation 924 may be accomplished bydetecting when the bottom surface 526 of the first alignment foot 522and the bottom surface 528 of the second alignment foot 524 contact theair bearing surface 110 of the substrate 104. The air bearing surface110 of the substrate 104 is used as a datum for determining when the airbearing surface 128 of the chip 106 is at the desired protrusion in thez direction. The distance that the first alignment foot 522 and thesecond alignment foot 524 extend from the bottom surface 520 of thepick-up chuck 502 is chosen so that the bottom surface 526 of the firstalignment foot 522 and the bottom surface 528 of the second alignmentfoot 524 will contact the air bearing surface 110 of the substrate 104when the air bearing surface 128 of the chip 106 is substantially at thedesired protrusion in the z direction.

In operation 926, responsive to detecting that the air bearing surface128 of the chip 106 is substantially at the desired protrusion in the zdirection in relation to the air bearing surface 110 of the substrate104, pushing the chip 106 into the adhesive is ceased. When the bottomsurface 526 of the first alignment foot 522 and the bottom surface 528of the second alignment foot 524 contact the air bearing surface 110 ofthe substrate 104, the first alignment foot 522 and the second alignmentfoot 524 prevent the pick-up chuck 502 from lowering any further,thereby preventing the chip 106 from being pushed any further into theadhesive.

The protrusion of the air bearing surface 128 of the chip 106 inrelation to the air bearing surface 110 of the substrate 104 is animportant parameter concerning the performance and reliability of themodule 100. The initial protrusion is affected by the dimensionaltolerances of the parts and the alignment of the chip 106 in the chipreceiving slot 126 in the substrate 104. Long term changes in theprotrusion are caused primarily by temperature and humidity effects. Inorder to be able to read and write to tape in accordance with desiredperformance characteristics of the module 100, the air bearing surface128 of the chip 106 must be aligned with the air bearing surface 110 ofthe substrate 104 within a protrusion tolerance dictated by the desiredperformance characteristics of the module 100. For example, there isgenerally no increase in read and write data error rates when the airbearing surface 128 of the chip 106 is aligned between about −4 μm andabout +11 μm from the air bearing surface 110 of the substrate 104. Anegative number (such as −4 μm) indicates that the air bearing surface128 of the chip 106 is lower than the air bearing surface 110 of thesubstrate 104, and a positive number (such as +11 μm) indicates that theair bearing surface 128 of the chip 106 is higher than the air bearingsurface 110 of the substrate 104). Too low of a protrusion (wherein theair bearing surface 128 of the chip 106 is below the air bearing surface110 of the substrate 104) may result in a reduction and/or loss ofservo, reader, and writer signals in the module due to Wallace spacinglosses. Too high of a protrusion (wherein the air bearing surface 128 ofthe chip 106 is above the air bearing surface 110 of the substrate 104)may cause excessive tape wear or damage or loss of servo signals.Generally, the air bearing surfaces 128, 110 are substantially alignedwhen the air bearing surface 128 of the chip 106 is aligned in the zdirection to within about −4 μm and about +11 μm from the air bearingsurface 110 of the substrate 104.

As an example, the air bearing surface 128 of the chip 106 is at thedesired protrusion in the z direction when the air bearing surface 128of the chip 106 is about 2 microns above the air bearing surface 110 ofthe substrate 104. In this example, the air bearing surface 128 of thechip 106 is positioned 2 microns above the air bearing surface 110 ofthe substrate 104 to allow for possible lowering of the air bearingsurface 128 of the chip 106 as the adhesive continues to cure afterbeing initially cured with U.V. light. However, the desired protrusionof the air bearing surface 128 of the chip 106 in the z direction couldbe greater or lesser than 2 microns above the air bearing surface 110 ofthe substrate 104, or below the air bearing surface 110 of the substrate104, or when the air bearing surfaces 128, 110 are coplanar. Lapping ofthe combined air bearing surface 102, which may be costly, is notrequired because the invention permits precisely positioning the chip106 in the substrate 104 to produce the desired protrusion.

The protrusion of the air bearing surface 128 of the chip 106 inrelation to the air bearing surface 110 of the substrate may bedesignated P2 at the first front corner 139 a (shown in FIG. 2) of thechip 106, may be designated P3 at the second front corner 139 b of thechip 106, may be designed P1 at the first back corner 139 c of the chip106, and may be designated P4 at the second back corner 139 d of thechip 106. The protrusions P2 and P3 at the front corners 139 a-b, aremore important than the protrusions P1 and P4 at the back corners 139c-d, because the back corners 139 c-d may later be removed from thecomposite air bearing surface 102 by a taperless grind operation(discussed below). If desired, a laser interferometer (which, forexample, may be obtained from Zygo Corporation) may be used to measureprotrusion tolerances. However, it is not necessary to measuretolerances when the air bearing surface 110 of the substrate 104 is usedas a datum (reference surface) for detecting when the air bearingsurface 128 of the chip 106 is at the desired protrusion in the zdirection, because the desired protrusion exists when the firstalignment foot 522 and the second alignment foot 524 contact the airbearing surface 110 of the substrate 104. Using the datum may be quickerthan individually measuring the protrusions P1, P2, P3, and P4, andadjusting the position of the chip 106.

The sequence 900 may also include operation 928, which comprises holdingthe chip 106, with the air bearing surface 128 of the chip 106substantially at the desired protrusion in the z direction in relationto the air bearing surface 110 of the substrate 104, and with the chip106 substantially aligned in the x and y directions with the chipreceiving slot 126 in the substrate 104. Due to the orientation of thebottom surface 520 of the pick-up chuck 502, during the holdingoperation 928 the air bearing surface 128 of the chip 106 issubstantially parallel with the air bearing surface 110 of the substrate104. In operation 930 the adhesive is cured to bond the bottom surface130 of the chip 106 to the bonding surface 170 of the chip receivingslot 126 in the substrate 104, with the air bearing surface 128 of thechip 106 substantially at the desired protrusion in the z direction inrelation to the air bearing surface 110 of the substrate 104, and withthe chip 106 substantially aligned in the x and y directions with thechip receiving slot 126 in the substrate 104. The chip 106 is heldfirmly during the curing operation 930 to prevent the adhesive frompulling the chip 106 downward when the adhesive shrinks as it is cured,and to keep the air bearing surface 128 of the chip 106 parallel withthe air bearing surface 110 of the substrate 104.

The curing operation 930 may comprise shining at least one U.V. lightsource on the adhesive for a prescribed period of time, for example 15seconds. As an example, the U.V. light source may use a 200 watt U.V.lamp (not shown) that has adjustable intensity. The light energy outputat the end of a U.V. light guide, for example, the first end 532 of thefirst fiber optic U.V. light guide 530, may be for example, aboutone-fifth of the light energy from the U.V. lamp. The optimal U.V. lightintensity is a function of the type of adhesive used, and is adjusted tonot be so high as to burn the outer surface of the adhesive, but to behigh enough to penetrate into the adhesive. The exposure time may beadjusted to be longer or shorter than 15 seconds. Applying U.V. light ofthe desired intensity for the prescribed time period quickly achievesbonding and fixes the location of the chip 106, but for many adhesives(such as Loctite 4303 adhesive), will not fully cure the adhesive. Bondstrength generally increases with time for at least 30 days. After theU.V. curing, the adhesive thickness between the bonding surface 170 ofthe chip receiving slot 126 and the bottom surface 130 of the chip 106may vary, for example, from about 5 μm to about 60 μm, with a nominalthickness of about 30 μm, due to manufacturing tolerances of thesubstrate 104 and the chip 106.

As an example, the curing operation 930 may include shining at least afirst U.V. light source on the adhesive proximate to the front 132 ofthe chip 106 for the prescribed period of time, and shining at least asecond U.V. light source on the adhesive proximate to the back 134 ofthe chip 106 for the prescribed period of time. In one example, U.V.light from the first end 532 of the first fiber optic U.V. light guide530 and U.V. light from the first end 538 of the second fiber optic U.V.light guide 536 are shined on the adhesive proximate to the front 132 ofthe chip 106 for the prescribed period of time, and U.V. light from thefirst end 544 of the third fiber optic U.V. light guide 542 is shined onthe adhesive proximate to the back 134 of the chip 106 for theprescribed period of time.

In an alternative embodiment, the curing operation 930 also includesheating the adhesive, at a temperature and for a time period suitablefor the adhesive, to further cure the adhesive. As an example, themodule 100 may be placed in an oven to further cure the adhesive. Thetemperature used for heating the adhesive and the duration of theheating may be chosen to achieve a desired bond strength while avoidingdegradation of any other adhesive bonds (for example, the bond betweenthe chip 106 and the closure 108). As an example, the temperature usedfor heating the adhesive may be from about 50° C. to about 80° C., andthe duration of the heating may be from about 1 hour to about 48 hours.The heating temperature may be determined based on characteristics ofthe adhesive. Although heating the adhesive may be performed as part ofthe curing operation 930, in other alternative embodiments heating ofthe adhesive may be performed in an additional curing operation, thatfor example, could be performed after the grinding operation 936(discussed below). Adhesive and process characteristics may beconsidered to determine whether it is desirable to perform heat curing,and to determine whether to perform heat curing as part of the curingoperation 930 and/or as part of an additional later curing operation. Inanother alternative embodiment, the curing operation 930 furtherincludes air and/or anerobic curing of the adhesive. Depending on theextent of the curing performed in the curing operation 930, the adhesivemay be partially cured, or substantially totally cured, after the curingoperation 930.

After the curing operation 930, the sequence 900 may also include theoperation 932 of ceasing evacuating air from the hole 548 in the bottomsurface 520 of the pick-up chuck 502, to release the chip 106 from thepick-up chuck 502. Also after the curing operation 930, the sequence 900may additionally include the operation 934 of ceasing clamping thesubstrate 104 in the substrate seat 506, for example by ceasing pressingthe substrate front clamp 514 and the substrate side clamp 516 againstthe substrate 104.

After the curing operation 930, (and after releasing the module 100 fromthe substrate seat 506 and the pick-up chuck 502), the sequence 900 mayalso include the operation 936 of grinding the substrate 104 and thechip 106 to remove a rear portion of the composite air bearing surface102 that includes the portion of the composite air bearing surface 102that is above the back 120 of the substrate 104. The portion of thecomposite air bearing surface 102 that is removed may be, for example,substantially rectangular. This operation 936 may be referred to as ataperless grind operation. (However, the surface produced by the grinddoes not have to be taperless.) More specifically, the taperless grindoperation 936 comprises grinding off a portion of the air bearingsurfaces 110, 128 of the substrate 104 and the chip 106, to produce thetail surface 157 of the chip 106, and the tail surface 158 of thesubstrate 104. The tail surface 157 of the chip 106 and the tail surface158 of the substrate 104 are substantially coplanar. The portion that isground off may be, for example, about 22.5 mm long from the first side122 of the substrate 104 to the second side 124 of the substrate 104, byabout 1.75 mm wide (from the back 120 of the substrate 104 to the frontedge 162 of the tail surface of the substrate 104, and from the back 134of the chip 106 to the front edge 161 of the tail surface of the chip106), by about 180 μm deep (from the air bearing surface 110 of thesubstrate 104 to the tail surface 158 of the substrate 104).

After the chip 106 and substrate 104 have been bonded and are partiallycured via U.V. exposure, they may sit at ambient conditions, (forexample, ˜20° C. and <30% R.H.), for a period of time, for example 24hours, prior to the taperless grind operation 936. During the taperlessgrind operation 936, the module 100 is exposed to water in a liquidcoolant. The water in the coolant can affect the bond strength and canalso cause adhesive swelling that results from adsorption of the liquidby the adhesive. After the taperless grind operation 936, the bondstrength may drop, for example, by about 40%, and the standard deviationof the bond strength may increase, for example, by about 38%.Additionally, after the taperless grind operation 936, the protrusion ofthe air bearing surface 128 of the chip 106 may increase, for example,on average about 0.9 μm. Also, it is possible for some bonds to fail dueto motion during the taperless grind operation 936. In some embodiments,to reduce the number of bonds that fail during the taperless grindoperation 936, additional U.V. curing, or heat curing, may be performedprior to performing the taperless grind operation 936.

III. OTHER EMBODIMENTS

While the foregoing disclosure shows a number of illustrativeembodiments of the invention, it will be apparent to those skilled inthe art that various changes and modifications can be made hereinwithout departing from the scope of the invention as defined by theappended claims. Furthermore, although elements of the invention may bedescribed or claimed in the singular, the plural is contemplated unlesslimitation to the singular is explicitly stated.

1. A tape head read/write module having a composite air bearing surface,the module comprising: a substrate having an air bearing surface, afront, a back, and a chip receiving slot, wherein the chip receivingslot has a front at the front of the substrate, a back at the back ofthe substrate, a first side, a second side, and a bonding surface, andwherein the air bearing surface of the substrate has a first portionadjoining the first side of the chip receiving slot, and a secondportion adjoining the second side of the chip receiving slot; and a chipthat has an air bearing surface, a bottom surface, a front, a back, andactive elements, wherein the active elements are located proximate tothe front of the chip, and wherein the chip is inserted in the chipreceiving slot in the substrate with the air bearing surface of the chipsubstantially aligned with the air bearing surface of the substrate;wherein the chip receiving slot in the substrate has a first side troughproximate to the first side of the chip receiving slot and a second sidetrough proximate to the second side of the chip receiving slot; and anadhesive layer attached to the bonding surface of the chip receivingslot and the bottom surface of the chip, wherein the adhesive layerfills at least a portion of the first side trough and the second sidetrough.
 2. The module of claim 1: wherein the chip has a tail surfacethat is substantially parallel to the air bearing surface of the chip,wherein the tail surface of the chip is located between the air bearingsurface of the chip and the back of the chip, and wherein the tailsurface of the chip is located in a plane positioned between the airbearing surface of the chip and the bottom surface of the chip; andwherein the substrate has a tail surface that is substantially coplanarwith the tail surface of the chip, wherein the tail surface of thesubstrate is located between the air bearing surface of the substrateand the back of the substrate.
 3. The module of claim 1 wherein theadhesive layer comprises a U.V. curable adhesive.
 4. The module of claim3, wherein the U.V. curable adhesive is a U.V. curable cyanoacrylate. 5.The module of claim 1: wherein the active elements have a surfacedefining the front of the chip, and wherein the active elements arecontiguous with a front of the air bearing surface of the chip; andfurther comprising a closure that has a back that is attached to thefront of the chip, and wherein the closure has an air bearing surfacethat is coplanar with the air bearing surface of the substrate and theair bearing surface of the chip.
 6. The module of claim 5, wherein theclosure has a front, and wherein the substrate has a first frontprotrusion that has a face and a second front protrusion that has aface, wherein the face of the first front protrusion and the face of thesecond front protrusion are substantially parallel with the front of thesubstrate and the front of the closure.
 7. The module of claim 1,further comprising a closure that has a front and a back, wherein theback of the closure is attached to the front of the chip, and whereinthe closure has an air bearing surface that is substantially coplanarwith the air bearing surface of the chip; and wherein a distance fromthe front of the chip to a back edge of the air bearing surface of thechip, is greater than a distance from the front of the closure to theback of the closure.
 8. The module of claim 1: wherein the chip has atail surface, wherein the tail surface of the chip is located betweenthe air bearing surface of the chip and the back of the chip, andwherein the tail surface of the chip is located in a plane positionedbetween the air bearing surface of the chip and the bottom surface ofthe chip; and further comprising a closure that has a front, a back, anda bottom surface, wherein the bottom surface of the closure issubstantially parallel to the air bearing surface of the chip, andwherein the bottom surface of the closure is located in a planepositioned between the tail surface of the chip and the bottom surfaceof the chip.
 9. The module of claim 1, wherein the first side trough hasa bottom, and the second side trough has a bottom.
 10. The module ofclaim 1, wherein the chip is substantially centered along a length ofthe substrate.
 11. The module of claim 1, wherein the front of the chipincludes a plurality of pads.
 12. A tape head read/write module having acomposite air bearing surface, the module comprising: a substrate havingan air bearing surface, a front, a back, and a chip receiving slot,wherein the chip receiving slot has a front at the front of thesubstrate, a back at the back of the substrate, a first side, a secondside, and a bonding surface, and wherein the air bearing surface of thesubstrate has a first portion adjoining the first side of the chipreceiving slot, and a second portion adjoining the second side of thechip receiving slot; and a chip that has an air bearing surface, abottom surface, a front, a back, and active elements, wherein the activeelements are located proximate to the front of the chip, and wherein thechip is inserted in the chip receiving slot in the substrate with theair bearing surface of the chip substantially aligned with the airbearing surface of the substrate; a closure that has a front and a back,wherein the back of the closure is attached to the front of the chip,and wherein the closure has an air bearing surface that is substantiallycoplanar with the air bearing surface of the chip; and wherein adistance from the front of the chip to the back edge of the air bearingsurface of the chip, is greater than a distance from the front of theclosure to the back of the closure.
 13. The module of claim 12: whereinthe chip has a tail surface, wherein the tail surface of the chip islocated between the air bearing surface of the chip and the back of thechip, and wherein the tail surface of the chip is located in a planepositioned between the air bearing surface of the chip and the bottomsurface of the chip; and wherein the closure has a bottom surface thatis substantially parallel to the air bearing surface of the chip, andwherein the bottom surface of the closure is located in a planepositioned between the tail surface of the chip and the bottom surfaceof the chip.
 14. The module of claim 13, wherein the tail surface of thechip has front edge, and wherein a distance from the back of the chip tothe front edge of the tail surface of the chip, is greater than adistance from the front of the closure to the back of the closure. 15.The module of claim 13, wherein the substrate has a tail surface,wherein the tail surface of the substrate is located between the airbearing surface of the substrate and the back of the substrate, andwherein the tail surface of the substrate has a first portion adjoininga rear portion of the first side of the chip receiving slot, and whereinthe tail surface of the substrate has a second portion adjoining a rearportion of the second side of the chip receiving slot.
 16. The module ofclaim 15, wherein the tail surface of the substrate is substantiallyparallel to the air bearing surface of the chip.
 17. The module of claim15, wherein the tail surface of the chip and the tail surface of thesubstrate are not parallel with the air bearing surface of the chip. 18.The module of claim 13: wherein the chip receiving slot in the substratehas a first side trough proximate to the first side of the chipreceiving slot and a second side trough proximate to the second side ofthe chip receiving slot; and further comprising an adhesive layer,wherein the adhesive layer fills at least a portion of the first sidetrough and the second side trough.
 19. A tape head read/write modulehaving a composite air bearing surface, the module comprising: asubstrate having an air bearing surface, a front, a back, and a chipreceiving slot, wherein the chip receiving slot has a front at the frontof the substrate, a back at the back of the substrate, a first side, asecond side, and a bonding surface, and wherein the air bearing surfaceof the substrate has a first portion adjoining the first side of thechip receiving slot, and a second portion adjoining the second side ofthe chip receiving slot; and a chip that has an air bearing surface, abottom surface, a front, a back, and active elements, wherein the activeelements are located proximate to the front of the chip, and wherein thechip is inserted in the chip receiving slot in the substrate with theair bearing surface of the chip substantially aligned with the airbearing surface of the substrate; a closure that has a front, a back, anair bearing surface, and a bottom surface, wherein the back of theclosure is attached to the front of the chip, and wherein the airbearing surface of the closure is substantially coplanar with the airbearing surface of the chip; wherein the chip has a tail surface,wherein the tail surface of the chip is located between the air bearingsurface of the chip and the back of the chip, and wherein the tailsurface of the chip is located in a plane positioned between the airbearing surface of the chip and the bottom surface of the chip; andwherein the bottom surface of the closure is located in a planepositioned between the tail surface of the chip and the bottom surfaceof the chip.
 20. The module of claim 19: wherein the chip receiving slotin the substrate has a first side trough proximate to the first side ofthe chip receiving slot and a second side trough proximate to the secondside of the chip receiving slot; and further comprising an adhesivelayer, wherein the adhesive layer fills at least a portion of the firstside trough and the second side trough; and wherein the substrate has atail surface, wherein the tail surface of the substrate is locatedbetween the air bearing surface of the substrate and the back of thesubstrate.